On a high-mobility 2D electron gas we have observed, in strong magnetic fields (ωcτ > 1), a parabolic negative magnetoresistance caused by electron-electron interactions in the regime of kBT τ / ∼ 1, which is the transition from the diffusive to the ballistic regime. From the temperature dependence of this magnetoresistance the interaction correction to the conductivity δσ Electron-electron interaction (EEI) corrections to the Drude conductivity σ 0 of 2D systems have been intensively studied over two decades. These studies were based on the theory of interactions in the diffusive regime,. Physically this condition implies that the effective interaction time, /k B T , is larger than the momentum relaxation time τ and therefore the two interacting electrons experience scattering by many impurities. In the ballistic regime, k B T τ / > 1, electrons interact when scattered by a single impurity. A theory of the interaction correction for such a case was only recently developed [2], and there have already been several experimental attempts to apply it to the conductance of high-mobility (large τ ) semiconductor structures [3,4,5,6,7,8]. An essential feature of this theory is that the impurities are treated as point-like scatterersthe condition which is not satisfied in structures where the impurities are separated from the 2D channel by an undoped spacer (unless the spacer is thick enough for the background impurities to dominate the scattering). There is then a question of how the interaction correction in the ballistic regime manifests itself in a smooth fluctuation potential.Introducing a long-range scattering potential is expected to suppress the interaction correction in the ballistic regime considered in [2]. This correction is caused by electron back-scattering, but in the case of a smooth potential the backscattering is significantly reduced. However, as shown in [9,10], applying a strong magnetic field increases the probability of an electron to return back and restores the interaction correction.

In this paper we examine electron-electron interactions in the intermediate regime T τ ∼ 1. It corresponds to the transition between the conventionally studied diffusive regime 1) and the ballistic regime recently developed in two theories.2, 3) In particular, we study the role of interactions in the 'metallic' behaviour of highmobility 2D systems with dρ/dT > 0: a 2DHG in GaAs/AlGaAs 4) and a 2DEG in vicinal Si. 5) We also investigate the manifestation of electron interactions in a 2DEG in GaAs/AlGaAs, in the conditions of a longrange fluctuational potential. 6)The interaction theory 2) considers coherent electron scattering from the Friedel oscillation caused by an impurity with a short-range potential and gives several predictions. Firstly, the logarithmic correction becomes a linear temperature dependence at k B T τ / > 1:where F σ 0 is the Fermi liquid interaction parameter in the triplet channel. Secondly, parallel magnetic field changes the sign of dρ/dT (the effect seen in recent experiments) by suppressing the correction in the triplet channel. The result is a universal correction δσ = σis the field of the full spin polarisation.The first experiments have been performed on a (311)A GaAs/AlGaAs heterostructure with a peak mobility of 6.5 × 10 5 cm 2 V -1 s -1 , which shows the crossover from 'metal' to 'insulator' at p ∼ 1.5 × 10 10 cm −2 . The hole density p in the 'metallic' region is varied in the range (2.09 − 9.4) × 10 10 cm −2 (the interaction parameter r s = 10 − 17). Fig.1(a) represents the temperature dependence of the resistivity, with the 'metallic' region obtained after subtracting the contribution of phonon scattering (significant only at higher densities). Linear fit of ∆σ(T ) in the region k B T τ / ≥ 1, Fig.1(b), gives the parameter F σ 0 shown in Fig.1(c). Experiments at field B ≥ B S show that the temperature dependence is linear, δσ = ασ B 0 T TF , with the slope α = 0.92 at lower densities close to the expected α = 1. We have also analysed the parallel magnetoresistance in small field in terms of theory 7) which predicts a parabolic positive magneroresistance in the bal- * A.K.Savchenko@ex.ac.ukThe comparison with experiment gives an independently determined value of F σ 0 shown in Fig.1(c). It is essential in theory 2) that the scatterers are pointlike. The fact that impurity scattering in our structure with a spacer of 500Å is dominated by a short-range potential, agrees with earlier findings that in high-mobility structures with large spacers it is the background impurities which determine the mobility. 8)We have also analysed the linear temperature dependence with dρ/dT > 0 observed in 2DEG in vicinal Si MOSFET.5) Fig. 2 shows an example of linear fit of σ(T ) and the value of parameter F σ 0 determined using the relation δσ(T ) = σ 0 1 + 9)The condition of short-range scattering cannot be satisfied in structures where the impurities are separated from the 2D channel by a thin spacer. In this case, a long-range scattering potential will suppress the interaction correction in the ...

Vascular endothelial growth factor (VEGF)-A is differentially spliced to give two functionally different isoform families; pro-angiogenic, pro-permeability VEGF-Axxx and anti-angiogenic, anti-permeability VEGF-Axxxb. VEGF-A splicing is dysregulated in several pathologies, including cancer, diabetes, and peripheral arterial disease. The bichromatic VEGF-A splicing-sensitive fluorescent reporter harboured in a transgenic mouse is a novel approach to investigate the splicing patterns of VEGF-A in vivo. We generated a transgenic mouse harbouring a splicing-sensitive fluorescent reporter designed to mimic VEGF-A terminal exon splicing (VEGF8ab) by insertion into the ROSA26 genomic locus. dsRED expression denotes proximal splice site selection (VEGF-Axxx) and eGFP expression denotes distal splice site selection (VEGF-Axxxb). We investigated the tissue-specific expression patterns in the eye, skeletal muscle, cardiac muscle, kidney, and pancreas, and determined whether the splicing pattern could be manipulated in the same manner as endogenous VEGF-A by treatment with the SRPK1 inhibitor SPHINX 31. We confirmed expression of both dsRED and eGFP in the eye, skeletal muscle, cardiac muscle, kidney, and pancreas, with the highest expression of both fluorescent proteins observed in the exocrine pancreas. The ratio of dsRED and eGFP matched that of endogenous VEGF-Axxx and VEGF-Axxxb. Treatment of the VEGF8ab mice with SPHINX 31 increased the mRNA and protein eGFP/dsRED ratio in the exocrine pancreas, mimicking endogenous VEGF-A splicing. The VEGF-A exon 8 splicing-sensitive fluorescent reporter mouse is a novel tool to assess splicing regulation in the individual cell-types and tissues, which provides a useful screening process for potentially therapeutic splicing regulatory compounds in vivo

Electron-electron interactions mediated by impurities are studied in several highmobility two-dimensional (electron and hole) systems where the parameter kBT τ / changes from 0.1 to 10 (τ is the momentum relaxation time). This range corresponds to the intermediate and ballistic regimes where only a few impurities are involved in electron-electron interactions. The interaction correction to the Drude conductivity is detected in the temperature dependence of the resistance and in the magnetoresistance in parallel and perpendicular magnetic fields. The effects are analysed in terms of the recent theories of electron interactions developed for the ballistic regime. It is shown that the character of the fluctuation potential (short-range or long-range) is an important factor in the manifestation of electron-electron interactions in high-mobility 2D systems.

COBAS ver2. Result: Fifteen patients were enrolled. In ten patients whose EGFR mutation was detected in liquid biopsy, the original EGFR mutation (exon 19 del or L858R) was detected in all patients. The detection rate of T790M was lower than that of the original EGFR mutation in liquid biopsy compared to that in tissue re-biopsy. The detection of T790M in serum exhibited a higher specificity (67%) and positive predictive value (50%) than that in plasma (50% and 40%, respectively). The detection sensitivity was similar in plasma and serum. Nine patients were treated with osimertinib. The RR was 77.8% and DCR was 100%. One patient who presented a response was positive for T790M in liquid biopsy (both plasma and serum) and negative in tissue re-biopsy. Conclusion: We suggest serum samples to be more useful than plasma samples for determining the effectiveness of osimertinib against relapse tumor sites because they were more reliable in the detection of T790M mutation at the relapse tumor tissue sites. Repeated tests with different samples and different methods may improve accuracy of T790M detection and will lead to the maximum benefit for the patient.